The accumulation of combustible gas in a dwelling or building, such as natural gas that is commonly found in a home or building, is extremely dangerous and may result in catastrophic losses of human life and property. Fortunately, this problem has been greatly reduced through the introduction of "odorized" natural gas. Odorized natural gas allows gas leaks to be detected by smell before large accumulations occur. Other situations, however, have not been solved by the introduction of odorized gas.
An especially insidious problem that still exists involves the accumulation of combustible gas within a sewer system of a home or dwelling. Sewer pipes, such as those leading up to a house, underneath a house, and within the walls of a house, often develop cracks or leaks that are undetectable. These cracks or leaks can go undetected for many years. This is because the cracks are normally out of view and often do not significantly degrade the performance of the sewer system.
Serious problems arise when a crack or leak in a sewer system is combined with a natural gas leak. Sewer systems normally include sewer vents that provide needed ventilation to the sewer system. Sewer vents normally extend to the roof of a building and are open so that sewer gasses may escape out of the sewer system. Whenever a crack or leak is present in a sewer system, the sewer vents act as a draw, like a draw from a chimney, such that gasses that reside near a crack or leak in the sewer system are swept or drawn into the sewer system through the opening of the crack or leak. Other conditions may also allow the escaping natural gas to migrate to the sewer system through its cracks and leaks. The presence of natural gas near such a crack or leak can result in catastrophic losses.
The crack or leak in the sewer system may introduce natural gas or allow natural gas to migrate throughout a house or dwelling in the various sewer pipes that run underneath and within the walls and floors. Unfortunately, because sewer systems contain traps to prevent the introduction of sewer gasses and odors within a house or building, the odorized natural gas cannot be detected within the house, even though it may actually permeate a large portion of the sewer system. An ignition source may result in substantial human loss and property loss.
The presence of natural gas in a sewer system is often detected by reports of natural gas being smelled outside of a house or building. This is often because the natural gas is being vented through the sewer vents. Because of the potential catastrophic effect of natural gas in a sewer system, gas companies often check the sewer vent of a house or building when a report of a natural gas leak is made.
Unfortunately, it is often extremely difficult and dangerous for workers to access such sewer vents on roofs. Falls from ladders and falls through rotten or deteriorated roofs are not uncommon when workers are attempting to check sewer vents for the presence of gas. On-the-job injuries are not uncommon from such activity, especially back injuries from carrying heavy ladders over a distance to access a convenient point to access a roof. The placement of ladders can also damage property, such as roof edges and landscaping, in addition to the dangers associated with detecting natural gas in a sewer system. It also take considerable time to access a roof in order to check for the presence of natural gas, resulting in fewer vents being checked.
The ability to safely and expeditiously check sewer vents for the presence of natural gas is important. Unfortunately, prior attempts to solve this significant problem have been inadequate in several respects. For example, prior attempts at using a retractable pole with an external hose and a chain mounted probe to sample the gas in the sewer vent have presented significant disadvantages. The external hose presents several problems that include the exposure of the hose to the elements which may result in holes or deterioration of the hose, which can result inaccurate readings potentially resulting in catastrophic consequences through false negative detections. The excess hose also requires more pumping power to retrieve a sample of the gas from the sewer vent, which results in an increase in the time that it takes to obtain a reading, and results in storage problems when the hose must be stored between uses.
The chain mounted probe presents the significant disadvantage and difficulty in lowering the probe into a sewer vent. This may result in false negative readings because of errors in inserting the probe in a vent. It becomes virtually impossible, unless one has a complete view, to verify that the probe has properly and sufficiently entered the vent. This also presents a considerable strain on the user's back to hold the entire pole assembly while guiding the probe into the sewer vent, and then holding the pole while waiting on a reading or detection.